export_ofoct.com

[00:00.96] As fall and winter come to some parts of the world, daylight hours grow shorter.

[00:08.40] This lack of light can cause seasonal depression.

[00:13.98] “It (is) a feeling of panic, fear, anxiety and dread all in one,” said Germaine Pataki.

[00:23.82] The 63-year-old woman living in Saskatoon, Saskatchewan, Canada, is among the millions of people estimated to have seasonal affective disorder, or SAD.

[00:39.22] To deal with her condition, Pataki uses yoga, walking, and an antidepressant medication.

[00:48.79] She is also part of a Facebook group for people with SAD and helps others deal with the condition.

[00:57.82] Pataki said, “This gives me purpose.”

[01:02.34] People with SAD usually have depression that begins in the fall and eases in the spring or summer.

[01:12.70] Changing the clocks back to standard time, which happens in autumn in the United States, can also cause SAD to start.

[01:23.07] Medical experts say there is a milder form, called subsyndromal SAD.

[01:31.84] There is also summer seasonal depression but less is known about that.

[01:39.27] In 1984, a team led by Dr. Norman Rosenthal, then a researcher at the National Institutes of Health, first described SAD. He invented the term.

[01:55.21] Scientists are still learning the causes of seasonal affective disorder.

[02:01.85] They have found that specialized cells in our eyes turn the blue wavelength of the light into neural, or brain signals.

[02:14.34] These signals affect mood and wakefulness, or alertness.

[02:21.77] Sunlight has a lot of blue light.

[02:26.29] So, when the cells sense this blue light, the alertness centers of our brains turn on.

[02:35.85] We feel more alert and possibly even happier.

[02:41.69] Kathryn Roecklein is a researcher at the University of Pittsburgh.

[02:48.07] She tested people with and without SAD to see how their eyes reacted to blue light.

[02:57.91] As a group, people with SAD were less sensitive to blue light than others, especially during winter months.

[03:08.54] That suggests a cause for wintertime depression.

[03:14.11] “In the winter, when the light levels drop, that, combined with a lower sensitivity, might be too low for healthy functioning, leading to depression,” Roecklein said.

[03:30.33] Miriam Cherry is 50 years old and lives in New York state.

[03:37.49] She spent the summer planning how she would deal with her winter depression.

[03:44.13] “It’s like clockwork,” Cherry said.

[03:48.39] “The sunlight is low.

[03:50.51] The day ends at 4:45, and suddenly my mood is horrible.”